Adding porous walls and polygons
Add porous objects that represent walls with a specified porosity and height.
Step-by-step guide
Porous walls and polygons represent walls with a specified porosity and height that are used during the 2D simulation process. A porous wall collinear with the boundary of a 2D zone overrides the boundary condition. It is possible to set parameters for the porous wall object that results in the full or partial removal of the wall during a simulation.
This example has a selection of porous walls and porous polygons that have varying properties.
These properties can be viewed or changed in the Properties window.
- Open the Properties window of the first porous polygon.
- Note the Porosity value.
This must be a value between 0 and 1, where 0 is impermeable and 1 is fully porous, meaning it has no impact on the flow. As an example, a low porosity in the range of 0.05 - 0.2 may be used to represent a building.
- Expand the Crest level drop-down to choose from 3 options: Infinite, Height, and Level.
This is the point up to which the porosity applies—above this, there will be no effect.
- Expand the Remove wall during simulation drop-down, which also has 3 options: Never, Fully, or Partially.
For the Partially option, only faces of the wall meeting the criteria are removed. This option can be used to simulate wall collapse.
- Select No rainfall to apply no rainfall within the polygon—an option only available for porous polygons.
To best demonstrate the effect of these objects, in this example, a simulation is run with the porous walls and polygons included.
As the water passes through the objects, the porosity takes effect. Those with lower porosity have a higher depth building up behind them and are the first to be removed when the height threshold is reached.